项目中有电话号码在拨打前会有一个提示框，boss觉得字号太小，看不清楚。奈何找来找去也没找到在ios8以后UIAlertView如何修改。今天用UIAlertController搜了一下，居然搜到了：
内容：[alertController setValue:msg forKey:@"attributedMessage"];
标题：[alertController setValue:msg forKey:@"attributedTitle"];
完整代码：
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"" message:self.telLabel.text preferredStyle:UIAlertControllerStyleAlert];
NSMutableAttributedString *msg = [[NSMutableAttributedString alloc] initWithString:self.telLabel.text];
[msg addAttribute:NSFontAttributeName
value:[UIFont boldSystemFontOfSize:17.0]
range:NSMakeRange(0, self.telLabel.text.length)];
[alertController setValue:msg forKey:@"attributedMessage"];
UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"呼叫" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:[NSString stringWithFormat:@"tel://%@",weakSelf.telLabel.text]]];
}];
[alertController addAction:cancelAction];
[alertController addAction:okAction];
[self presentViewController:alertController animated:YES completion:nil];
